Method for Data Communication of Bus Users in an Open Automation System

ABSTRACT

A method for data communication of bus users of an open automation system such that any bus user with an individual and interactive communication may be connected, provides for a communication controller (KC) made up of at least one freely-programmable communication-ALU (RPA, TPA, PEA), with several commands being encoded on a command code for the communication-ALU optimized for particular communication functions, and logic function blocks (FI, Z, V, CRC) arranged in parallel in the communication ALU (RPA, TPA), which carry out particular communication functions, the communication functions not being definitively defined but rather being formed on the basis of the freely-programmable and communication function optimized communication ALUs (RPA, TPA, PEA), wherein several commands are carried out in a system cycle and transitions between various networks can be carried out.

The present invention primarily relates to a method for datacommunication, in particular for coupling bus users of an openautomation systems, and a freely programmable communication processoraccording to claim 1 or 9. Furthermore the present invention relates toa method for data communication, in particular for configuration, and anapparatus with a flexible communication structure, in particular aprogrammable controller, according to patent claims 14 and 19. Finallythe present invention relates to a method and a device for datacommunication, in particular for synchronization of communicating amongeach other bus users of an automation system with distributed controlfunctions over a serial data bus, according to patent claims 20 or 21and 24.

Already for a longer time in the control and automation technology fieldbusses and Ethernet are used, in particular the extension regardingReal-Time Ethernet for data communication between individual units beinginvolved in controlling a process. Examples for known field busses areCAN-Bus, profibus, modbus, DeviceNet or Interbus. The communication ofthe units is carried on the field bus/Ethernet on the basis of specifiedprotocols. In order to comply with demands for open systems fornetworking, it is necessary to provide simple and low-cost systems fornetworking in order to make industrial appliances capable fornetworking. This demand is particularly important with respect tocoupling drive components, such as between drive controls, power unitsand transmitters in NC machine tools and robots, regarding which aplurality of interpolating axles have to be operated synchronously. Intimes of increasing networking of most different technical systems thedemand for standardized structures in the industry grows accordingly.

One example for this requirement is the field bus according to theso-called Actuator-Sensor-Interface-standard, in short ASI-standard.This field bus concept is specifically designed for making binarysensors or actuators directly bus-capable, which could not be obtainedwith other field bus systems up to now. An automation system consists ofhardware components being connectable to said bus system, in particularmotors, sensors, actuators, inter alia—that is the processenvironment—which by acting together with one or more superior controlsconstitute an automatic production process. The bus master then takesover all tasks being necessary for the processing of the bus operation.As a rule the bus master is separated from the actual control unit forcontrolling the hardware components.

In order to easily obtain an open and flexible operating mode of thesystem, wherein the hardware components may be exchanged withoutchanging the control programs, in DE 198 50 469 A1 an automation systemand a method for accessing the functionality of hardware components isdisclosed, wherein as a mapping of the current functionality of hardwarecomponents these provide a system connection unit with function objectseach, wherein the function objects are provided for accessing thefunctionality of the hardware components over the bus system. In orderto implement the hardware components as “plug and play” modules it isnecessary to provide a special function block directly placed in thehardware component, on which the function objects are operable givingaccess to the functionality of the hardware components. This specialfunction block is implemented in the form of the system connection unit.This system connection unit is coupled to a bus system of the automationsystem such that for example communication data can be transmitted froma management system to the hardware component as well as from and to allfurther components coupled to the bus system. By the system connectionunit thus it is possible to substitute or to add, etc., hardwarecomponents without changing existing structures of the automationsystem. Furthermore special node elements, which were required up to nowbetween the management system and the hardware components, can be leftout. For a network transition the system connection unit provides amemory for storing protocols required between both bus systems. Thus ina very simple way a network transition between ETHERNET (data transferrate 10 Mbit/s), in particular the FAST ETHERNET (data transfer rate 100Mbit/s—standard IEEE Std. 802.3-1998), and the profibus may be obtained.The embedding of the system connection units assigned to the hardwarecomponents in their environment may be designed such, that the functionobjects comprise at least one first function object for generating aminimal functionality of one hardware component, at least one secondfunction object for interconnecting function objects and at least onethird function object for listing function objects provided in thesystem processing unit and/or in removed system processing units and/orin removed computers. The particular function of the function objects isto enumerate, i.e. to enquire the functionality sum of the system. Forexample the function objects are designed as so-called DCOM-objects(Distributed Component Object Model) or as so-called OLE-objects (ObjectLinking and Embedding). Furthermore the system connection unit providesa runtime-system as well as a protocol-processing unit (Profibus,UDP/IP, RPC). Therefore the system connection unit represents a standardmodule, which has to provide protocols specified for the field bus, andwhich is often quite complex and therefore relatively expensive.

In order to allow a fail-safe communication of units involved in asafety-critical process, wherein at the same time the use of standardmodules as bus masters is permitted, in DE 199 28 517 C2 a managementsystem is disclosed, wherein the bus master is connected to the fieldbus separately from a first control unit and a signal unit, wherein thefirst control unit is arranged upstream of a signal unit with respect toa circulation direction of the telegram traffic, and wherein the firstcontrol unit provides means to substitute telegram data being addressedto the signal unit with fail-safe telegram data. It is then possible toconnect said first control unit as a simple bus user, i.e. without a busmaster functionality, to the field bus. Furthermore the control systemprovides a second control unit to control non-safety-critical processes,being connected to said field bus separately from said first controlunit. Apart from other already known components the second control unitprovides a micro controller as well as a master-protocol-chip. In thepresent case the master-protocol-chip provides a bus masterfunctionality for an interbus and is named “bus master”. Suchmaster-protocol-chips are obtainable as standard modules from differentmanufacturers. A communication module contained in the first controlunit provides a slave-protocol-chip being connected to the field bus onthe input side via a first bus interface and via a second bus interfaceon the output side. The protocol chip corresponds to the protocol chipscontained in signal units, which connect safety-relevant devices to thefield bus as bus users. In order to provide a slave-to-slavecommunication between bus users in a field bus with sequentiallycirculating telegram traffic, wherein no bus user has a bus masterfunctionality, the protocol chip of a bus user, which intends to senddata to other bus users, will be supplemented with a transmitting memoryand if applicable with a receive memory. The operating principle of thecirculating telegram traffic is accordingly based on the arranged in thesame way slave-protocol-chip in each bus user, often named as “SerialMicroprocessor Interface” (SUPI). Because of using a standard moduleobtainable from different manufacturers, the cost for a control systemmay be kept low; altogether the cost for the bus master and the signalunits, which have to provide specified protocols for the field bus, arecomplex and relatively high.

A similar solution is disclosed in DE 299 07 909 U1 with respect to atracking system implemented in a production system based on plug-inboards. In detail each plug-in board provides a microprocessor, a memoryunit storing process data and being connected to said microprocessor, asensor bus interface (RS 485) and a field bus interface (RS 485) bothbeing connected to said microprocessor, a service interface (RS-232) forconnection to a modem and an interface (ISA-bus interface) forconnecting the microprocessor to a host computer. The integratedfield-bus interface, or the sensor bus interface, each provide anISO-interface and a field bus data processor (SPC 3), in the presentexample a profibus-data-processor. A machine control is optionallyconnected to the plug-in board via the integrated profibus interface orto sensor-electronic units via an II/O-box. The intelligentsensor-electronic-units each allow the supply of one sensor, thecollection of sensor data, the pre-processing of measuring signals(signal filtering, signal amplification, etc.) and the simple signalanalysis (digital filtering, collecting peak values, etc.). Therefore anintelligent sensor-electronic-unit implies being a module providing anown micro-controller, filter, amplifier, power supply and a sensor businterface. The sensor-electronic-unit may be newly parameterized via theplug-in board before each processing. This concerns for example theamplification factors, the filtering values and the clearing of severalinput signals to one sum signal. By the profibus interface themonitoring may be synchronized to the processing operation. Viaso-called automated setting routines the monitoring system may be easilyimplemented in the production appliance. The automated setting routinesfor example perform the speech perception on the controller and theconnected to it speech switching, the recognition of the sensors on thesensor bus and the automatic configuration of the amplification andfilter values. The inputs and outputs of the programmable logiccontroller (SPS) are assigned automatically and the time of a real timeclock on the plug-in board will be automatically coordinated with thetime of the host computer. The plug-in board allows to monitor forexample up to four sensor channels, wherein for the sensor bus interfacea data rate up to 460.8 kBaud, at the same time having a highinterference immunity, may be obtained with the communication processor.Preferably the microprocessor of the plug-in board processes data inHamming code with a Hamming distance of 4 and carries out the encodingand decoding. Between the microprocessor and the ISA-interface towardsthe host computer an address decoder is included carrying out theencoding and decoding of address and memory accesses in a PC in a per seknown way. The power supply of the plug-in board is carried out via theISA-interface, across which the communication to the host computer iscarried out as well. Because the plug-in board has its own processorbeing in charge of the monitoring, the CPU of the host computer shallnot be reserved for processing power. A real-time capable sensor busprotocol is defined for the communication with thesensor-electronic-units. Thus the enquiry of the measuring data as wellas the controlling and parameterizing of the sensors with definedresponse times is made possible. The monitoring data are processed in acycle of 10 ms and the pre-processing of sensor data allows a scanfrequency below 1 ms. Thus a response time below I ms may be guaranteedfor a collision monitoring. Beside the synchronization data also processspecific axle signals can be transmitted via the field—or the profibusin a preferable way like torques, motor currents and axle speeds. Theprotocol allows for example the enquiry of up to eight different axles.Via the field bus the required control data can also be directlydelivered out of the control core of the machine control to themicroprocessor of the plug-in board. In this case no specific sensortechnology is needed and the sensor bus interface on the plug-in boardmay be left out. Via the service interface all settings, softwareupdates as well as process visualization may be carried out. In casesaid service interface is designed as a modem interface then teleserviceand telediagnostic service functionalities are available via a modem.Accordingly the system becomes fully operable and parameterizable underremote control. The visualization of process data may be performed by aprogram on the host computer (controller, industry-PC). As the plug-inboards and the intelligent sensor-electronic-units, which have toprovide protocols specified for the field bus, are complex andrelatively expensive this may be deemed a disadvantage again.

Furthermore in DE 198 31 405 A1 a control system with a personalcomputer is disclosed, which provides for processing a control programat least one PC-processor, one program memory and one data storage andwhich provides a communication processor for the connection to a fieldbus, to which sensors and/or actuators for controlling a process may beconnected. For the communication on the field bus a plug-in board isinserted in the PC, which is connected to an internal PCI-bus, whichprovides data-, control- and address lines. Via a PCI-bus connection andthe internal bus the PC-processor communicates with the components ofthe plug-in board. The communication processor is arranged on theplug-in board and automatically carries out a cyclic data transfer onthe field bus after a corresponding parameterization of the PC-processorand mainly consists of an ASIC. The communication processor is operableas a master on a field bus with cyclic data transfer like the PROFIBUSDP and functions as clock source when collecting process data. Further amemory is provided in which process data delivered on the field bus arestored. This memory then stores a current process map, which thePC-processor may access at any time. In order to relieve thePC-processor of the polling of incoming process data or of monitoringthe field bus, a control unit is provided. The control unit may beimplemented through a hardware circuit being parameterisable, but alsothrough an expansion of the communication processor program in form of asoftware solution. The hardware circuit then comprises a small RAM beingembedded in the address space of the PC-processor and therefore may bedirectly addressed by the PC-processor and a programmable logic module,which according to a corresponding parameterization stored on the RAMmonitors the cyclic data transfer on the field bus and/or incoming dataon the field bus. When starting the control program in the programmemory the PC processor accesses the RAM and sets the corresponding bitstherein, thus determining the function of the control unit as required.By this parameterization it may be determined for example in which casesthe control unit has to generate an interrupt, which is transmitted viathe PCI-bus connection and on the PCI-bus to the PC-processor. Thus itmay be determined, in which cases the PC-processor shall be prompted bythe control program to further process data received on the field bus.In case of active process control the communication processor as amaster continually polls all users on the field bus, for example sensorslike a flow meter or a level meter converter, actuators like supply ordischarge valves in a tank, which are operated as slaves. In case thecommunication processor read in process data of a slave, it intends tostore those in the memory cells of the memory provided for theindividual process data. The logic block of the control unit reviews bythe address of the write access, if an interrupt has to be generated incase of a change of the individual process data. This review can easilybe carried out, because the process data of each slave are stored atfixed memory locations within the memory. If an interrupt has to begenerated in case of a particular data change, a data comparatorimplemented within the logic block compares data put on the bus by thecommunication processor with previous process data, which previouslyhave been read out of the memory by the logic block. Because thecomparison of currently received data to previous process data as wellas the interrupt-generation is carried out by a control unit implementedin hardware-form thus a very quick response of the control system to thechange of process data is possible in a favorable way. The disadvantageagain is that the communication processor and the control unit, whichhave to provide specified protocols for the field bus, are complex andtherefore relatively expensive.

The use of (Fast)-Ethernet transfer technology is also known regardingthe networking of different communication systems. For example in DE 10047 925 A1 a method for the real-time communication between severalnetwork users within a communication system with Ethernet-physics isdisclosed, wherein a master unit and one or more slave units communicateamong each other by transmitted over the network telegrams, a cyclicalexchange of telegrams takes place with equidistant sampling points,wherein each slave unit is synchronized to the master unit by a sharedtime basis and an access control for the transmit and receive modebetween the network users is performed by a time slot-access method. Inthe automation technology the demands on the performance ofcommunication systems are particularly high, for example regarding thecoupling of driving components. The data transfer time, in the controlloop taken into account as lag time, is an especially importantparameter when exchanging data between transmitters, power units and adriving control. The smaller this lag time the higher a dynamic volumecan be obtained by the control system. Because in the automationtechnology a highly accurate compliance with real-time conditions isrequired as well as a high data transfer safety, the standardizedtransmitting layer 2 (telegram frame and access method) of the(Fast)-Ethernet, which does not comply with these demands, shall bedefined completely new by a new telegram frame and a new access controland with this the Ethernet-physics is used as a basis for a real-timecommunication between, for example, driving components. Thecommunication between the control unit and the transmitters and thepower units as well as the connection to a motion control can then beimplemented. In order to obtain a cyclical data transfer with samesampling times, a shared time basis for the master and all slaves isimplemented. The synchronization of the slaves to the master is carriedout by specifically marked up, time wise defined telegrams of the mastersent to the slaves and individually parameterized timing registerswithin the slaves. The user data can be transmitted on a telegram frame,which provides—beside the slave addressing and the telegram lengthinformation—the securing of the data integrity by, for example, aCRC-check sum and further security-related data ranges. An applicationprocessor may not only evaluate the data on the telegram frame, but alsoby a communication block, thus providing a second initiating channel.Although the applied transfer technology according to theEthernet-standard in principle only permits point-to-point-connections,the establishment of networks can be obtained by using network nodes(so-called HUBs) as used in (Fast)-Ethernet-networks, wherein several oreach network user has a switch unit to establish a network node, whichserves for the transmission of the telegrams in the direction of anothermaster unit or further slave units. Then also hierarchical networks withpoint-to-point-connections with Ethernet-physics connected via networknodes can be established for the realization of a real timecommunication within larger network topologies. This is also useful fora networking or coupling of a distributed driving system, wherein afirst communication system comprises a numeric motion control as amaster unit and at least one control unit as a slave unit, wherein eachcontrol unit serves as a master unit of a further communication system,which provides at least one power unit to drive a motor and an assignedtransmitter system as slave units. Via Fast Ethernet-line drivers withineach network user and possible network nodes the telegrams reach theparticular protocol components, which process the telegram protocol andin which the time slot access method is implemented. If the protocolcomponent is independent from a microprocessor of the slave-application(the actual power unit), particular application events may be initiatedby the control-bits of the telegram frame within the slave withoutrequiring the assigned to the slave microprocessor or correspondingsoftware. This corresponds to a second initiating channel like it may berequired for particular security-related applications (i.e. emergencystop, etc.)

In DE 100 04 425 A1 a network with a plurality of network users, forexample sensors and actuators, is disclosed, which are connected amongeach other over the network for the data transfer. In order to obtain animproved precision of the clock synchronization, the first telegramcomprises a corrected by a transmission time delay time of a firstnetwork user, and a second network user is designed such that itmeasures the time delay since reception of the first telegram and tocorrect the time received in the first telegram by the lead time and thereception time delay. If the second network user is furthermore designedsuch that it is able to send a second telegram for clock synchronizationto a third network user, which contains a received time corrected by thelead time and the delay between reception of the first telegram andsending of the second telegram, thus an iterative re-sending of alwayscorrected clock times from network user to network user is feasible.Furthermore start and end of the lead time of a telegram can be definedas the point of time, at which a characteristic field of a telegram witha defined spacing from the telegram beginning leaves aMedia-Independent-interface of the first network user, or enters into aMedia-Independent-interface of a second network user. Measuring thetransmission time delay, lead-time and reception time delay notdepending on the length of each telegram may be advantageously. If thenetwork components comply with the Ethernet-, Fast-Ethernet- orGigabit-Ethernet-specifications, the type-field of the telegram can beused advantageously as a characteristic field of the telegram. A networkuser, in particular a field device, can be provided with several ports,in particular four ports, for the connection to further networkcomponents. Then an interface, a so-called microprocessor-interface, canbe provided for the connection of the ports with a network user internalprocessor bus and a control unit, a so-called switch-control, whichinitiates a telegram re-direction between the ports and themicroprocessor-interface. This has the advantage that network users, inparticular field devices, can be interconnected in a linear structure asusually done by field bus users. A separate switch, like required in astar-shaped structure, is not necessary. The integration ofswitch-functions within the network users has the advantage that inparticular regarding Ethernet the CSMA/CD-access control can bedeactivated and the network obtains a deterministic behavior. With thisthe range of applications of network users and the network is extendedto those applications, where real-time behavior is required. A gatewayfor coupling network areas of different physics and with differentprotocols is not necessary. The communication with application-specificswitch units of network users is performed by a microprocessor bus, towhich a RAM, a microprocessor and a microprocessor-interface areconnected. Task of the microprocessor is to process application programsand communication functions, for example the processing of TCP/IP. Afurther task may be the management of transmission and receptions listsof telegrams of a different priority within an external RAM. Furthermorefour Ethernet-controllers are arranged in an ASIC of the communicationinterface. Each of those Ethernet-controller enters the data bytes of afully received telegram into a reception list within the RAM through amultiplexer, a DMA-controller, which is also called a DMA 2-control, andthe microprocessor-interface. The microprocessor accesses the receptionlist and evaluates the received data according to an applicationprogram. The microprocessor-interface forms the essential interfacebetween the Ethernet-controllers and the microprocessor bus. It controlsand arbitrates the write and read accesses, which are carried outthrough the DMA-controller or the DMA-controller on the RAM. IfDMA-requests of both DMA-controllers are sent, themicroprocessor-interface decides on the access rights of bothDMA-channels. The microprocessor can further write parameter-registersvia the microprocessor-interface, which serve for the operation of thecommunication interface of the network user. A device of theEthernet-controllers, named as Transmit-Control, comprises a controlunit, which performs the transmission of telegrams, repetitions,transmission abortion, etc. It forms the interface between the internalcontroller cycle and the transmit cycle. For storing atransmit-status-information for low-prior and high-prior telegrams atransmit-status-register is provided in this device. If a telegram hasbeen sent fail-safe via the port, a corresponding interrupt will begenerated. The Media Independent Interface (MII) integrates theMAC-sublayer of layer 2 according to the seven-layer-model, i.e. thedata-link-layer. This forms an interface to a block for the physicaldata transfer. Further the MI comprises a transmit-function-block aswell as a receive-function-block. In addition a MAC-control-block, anaddress filter, a statistical counter and a host-interface areintegrated. Control and configuration data can be transmitted to theblock via the MII and status information can be read from it.

In distributed automation systems, for example in the sphere of drivetechnology, specific data must be received by specific users at aparticular point of time (i.e. real-time critical data) and must beprocessed by the recipients. According to JEC 61491, EN61491 SERCOSinterface-technical abstract (http://www.sercos.de/deutsch/indexdeutsch.htm) a successful real-time critical data transfer of thementioned kind can be provided in distributed automation systems. Fromthe automation technology synchronous, clocked communication systemswith equidistance-features are known as, for example, disclosed in DE101 40 861 A1 for a system and a method for transmitting data betweendata networks. In detail the first data network provides first means forthe data transfer in at least one first transmission cycle, wherein saidfirst transmission cycle is divided into one first range for thetransmission of real-time critical data and a second range for thetransmission of non real-time critical data. The second data networkprovides second means for the data transfer in at least one secondtransmission cycle, wherein said second transmission cycle is dividedinto a third range for the transmission of real-time critical data and afourth range for the transmission of non-real-time critical data. Forthe coupling of data networks with the same or different communicationprotocols, for example, Ethernet-data-networks, in particular isochronereal-time Ethernet-communication systems, with PROFIBUS-data networks orisochrone real-time Ethernet data networks with SERCOS-data networksand/or FIREWIRE-data networks or PROFIBUS-data networks and/orFIREWIRE-data networks with SERCOS-data networks, finally a couplingunit (Router) is provided for transmitting real-time critical data fromthe first range to the third range. The possibility to be able totransmit real-time critical data from one data network to another, isused for transmitting cycle-synchronization-telegrams from one clocksource of one data network to the other data network, in order to alsosynchronize local relative clocks by the cycle-synchronization-telegramsin the other data network. Therefore the different data networks haveown clock sources each. Because of the cycle synchronization across datanetworks in each data network user a relative clock can be implemented,which represents an unambiguous time across the system. Based on thisbasic mechanism events in both communication systems can be collectedwith a shared time-related understanding or time-related switch-eventscan be initiated in the own or the other data network. The accuracy ofthe relative clock corresponds at least to the accuracy of onetransmission cycle. The router may then be designed as a discrete deviceor as an integral part of one user of one of the data networks, whereinalso the routing of acyclic, demand controlled communication, forexample Remote Procedure Calls (RCP), between the data networks isfeasible and the corresponding communication may be carried out withproprietary and/or open protocols.

Automation components (i.e. controllers, drives) in general have aninterface to a cyclically clocked communication system. One processlevel of the automation component (fast-cycle, for example positioncontrol in a controller, speed and torque control of a drive) issynchronized to the communication cycle, through which the communicationcycle is determined. Other algorithms of the automation componentrunning slower (slow-cycle, for example temperature control) may onlycommunicate with other components via this communication cycle as well(for example binary switch for fans, pumps), even if a slower cyclewould be sufficient. By using just one communication cycle fortransferring all information across the system high demands arise withrespect to the bandwidth of the transmission path. Accordingly for eachprocess or automation level the system components use just onecommunication system or one communication cycle (fast-cycle) forcommunication, all relevant information being transmitted in the givencycle. Data, required only in a slow-cycle, can be transmitted gradedlyby additional protocols to limit the bandwidth requirements. In DE 10147 421 A1 a method is disclosed wherein a second user in a switchabledata network controls one first user in a switchable data network,wherein the control loop can be closed over the switchable data network.For this purpose the communication between users of the switchable datanetwork is provided via one or more point-to-point connections withinsynchronized to one another transmission cycles. For the communicationof actual and ideal values, or of correcting variables over the datanetwork the real-time-capable band of a transmission cycle is used andthe communication of required for the control data telegrams is carriedout within determined time windows. Further also a guide value may betransmitted over the switchable data network, which is generated by oneof the users of the data network for one or several users of the datanetwork. This could be, for example, the collection of an actual valueof an axle, i.e. of a so-called master axle, of a facility. Based onthis actual value the particular user generates a guide value, whichserves for controlling so-called slave-axles. The functionality of sucha control, for example a programmable logic controller, a motion-controlsystem or a numerical control may also be integrated in a drive. Apartfrom the coupling of an input/output-station to a control unit also arelative clock may be generated within one user. The relative clock isgenerated by a master clock and cyclically distributed within thenetwork thus implementing the same set of time in all users involved inthe network. The time basis for the relative clock is then given by thesynchronous transmission cycles and/or subdivision of transmissioncycles into time slots. Based on this shared time, events may becollected with time stamps (for example edge identification of digitalI/Os) or switching processes (for example switching of digital/analogoutputs) may be marked with time stamps and the switching output may beprocessed based on this shared relative time. Within the real-timecommunication several communication cycles are potentially provided inorder to implement different “quality of services”, like for example: 1ms-cycle for sync connections (guide value via bus), speedtarget-/position target-/I/O-interface for time-sensitive axles, fastI/O-coupling or 4ms-cycle for non-time-sensitive axles (frequencyconverter, simple positioning axles), application data for example:emergency-stop-control, shared shifting register (product pursuit),driving (for example modes of operation) in distributed systems,instruction of new drilling operations (for example drill depth) ofautomatic drilling machines or asynchronous and/or event-controlledcycle for projection-data and -events or data and routines for errorhandling and diagnosis.

In order to provide a method for making up a communication system forindustry automation based on Ethernet having an essentially determinablecommunication behavior, response times in the lower ms-range and lowcost regarding the communication nodes, finally in DE 100 55 066 A1 amethod for multidirectional exchange of information between users (forexample programmable controllers) is disclosed. Dependent on the size ofthe sent Ethernet-data-packet (telegram) it will be subdivided intoseveral smaller packets (short telegrams) and at least one controlinformation will be added to each packet, said smaller packets will betransmitted to their target in several cycles and if applicable will beput back together to the original Ethernet-data-packet by means of thecontrol information. All telegrams, the length of which is longer thanthe length of the short telegrams, will be subdivided and all shorttelegrams have the same fixed length. Source and target of the shorttelegram, no matter whether subdivided or not, independent of in howmany short telegrams it was subdivided, and the current number of theshort telegram can be learned from the control information. For themultidirectional exchange of information between users (for exampleprogrammable controllers), wherein a user may be assigned to anindustrial domain switch (IDS), which is connected to the IDS via anEthernet-connection, the IDS are structured as a network via aconnection in conformity with Ethernet and each IDS obtains a time wisedetermined transmission right controlled by a determined, cyclicframework. When starting the system or restarting it (Power On or Reset)the assignment of a transmission right will be negotiated between theIDS via a management function by management telegrams, regarding whichthe IDS recognize that those are management telegrams. The entirecontrol logic of the IDS may be integrated into a high-integratedelectronic component.

As shown by the foregoing description of the present state-of-the-art,in the automation technology various interfaces with their physicalcharacteristics and transmission protocols are defined for thecommunication between individual devices and are standardized accordingto international specifications or become established as industrystandards. These systems are generally called field bus systems, whereinalso Ethernet-based technologies belong to those. The interfaces aremade up in form of dedicated communication-controllers, partly with CPUas integrated circuits (communication-processor) as shown for example inDE 198 31 405 (ASIC: ASPC2), DE 299 07 909 (ASIC: SPC3), DE 199 28 517C2 (ASIC: SUPI), DE 100 04 425 A1. As well the entire interface is oftendesigned as an exchangeable module, comprising a connector, physicalinterface, dedicated communication-controller, microprocessor withmemory and transfer logic to the CPU of the programmable controller, asa rule a Dual-port Memory. This module realizes exactly one specifictransmission protocol and has to be specifically developed in itsentirety to comply with this requirement. As a rule thecommunication-processor comprises only one specificcommunication-controller for a specific field bus system, however in themeantime circuits are available, which comprise several of thesededicated communication controllers, as it is disclosed in the U.S.patent application Ser. No. 09/780,979 for a communication-controlleraccording to the CAN-standard and a communication-controller accordingto the Ethernet-standard. As a rule then specific hardware and softwarecomponents are required together with some expensive componentsparticularly adapted to communication requirements, like HUB and linedrivers, Ethernet-controllers, Media Independent Interface for theconnection to another network (public data network, other LAN or a hostsystem), field bus interfaces or sensor bus-interface, in particularSerial Peripheral Interface with Master- or Slave-protocol-chips, aswell as the conversion of corresponding network-access-protocols, forexample CSMA/CD (Carrier Sense Multiple Access/Collision Detection),Token-Passing (binary pattern as authorization mark) or TCP/IP(Transmission Control Protocol/Internet Protocol) in for the field busspecified protocols. Almost no attention is paid to the development ofsuch a circuit or a communication interface permitting an individual andcomfortable matching of communication functions independent of aspecific field bus system. As a rule the communication-controllerimplements only one specific field bus system for the communication ofthe usual SPS-function blocks, wherein for example drives aresynchronized to each other via fast, deterministic and jitter-freecommunication connections. This is carried out by detecting a specificdata or event in the communication controller, which initiates thedownstream CPU by an interrupt to execute the synchronous drivefunctions, like measuring the position or the output of the correctingvariables. This method has the disadvantage that the accuracy of thesynchronization is decisively affected by the interrupt-latencies of theCPU, in particular when using operating systems, which block theinterrupts for specific periods of time. Therefore in practice low-costmethods and communication interfaces are missing for an automationsystem operable in real-time, which ensures an individual, in particularautomatically adjustable, interactive communication or allows a simpleexchangeability or function blocks for an automation system operable inreal-time, which also without additional hardware-function modules andwithout costly adaptation of interfaces establish quick and economicallydemanding automation solutions. In particular this is important, becausethe telecommunication and computer industry, in particular in the sphereof automation and drive technology, can be deemed very progressive andinnovative industries, which very quickly pick up improvements andsimplifications and implement those.

Object of the invention is to design a method for data communication ofbus users of an open automation system such that the connection of anoptional number of bus users to an individual, interactive communicationmay be permitted. Further objects are to provide exchangeability ofparts of the apparatus or to provide an automatic and highly accuratesynchronization.

The task according to the invention is solved according to claim 1. Forthis purpose a method for data communication is provided, in particularfor the coupling of communicating among each other bus users of an openautomation system with distributed control functions via a serial databus, said bus users cooperating via a communication controller with asuperior control unit, wherein:

-   -   the communication-controller is made up of at least one        freely-programmable communication ALU,    -   several commands are encoded on a command code for the        communication ALU and which is optimized for particular        communication functions,    -   logic function blocks are arranged in parallel in the        communication ALU which carry out particular communication        functions,        said communication functions not being definitively defined, but        rather are formed on the basis of the freely-programmable and        communication function optimized communication ALUs, whereby        several commands are carried out in a system cycle and        transitions between the various networks can be carried out.

According to the invention said method provides in a very simple way themaking up of a “quasi firm” communication controller, said communicationcontroller being made up of one or several freely-programmablecommunication ALUs (Arithmetic and Logic Unit), said ALUs providing acommunication tasks optimized command set and hardware architecture.Therefore the following advantages are provided according to theinvention:

-   -   The development, production and sale of such a circuit may be        carried out independent of a particular field bus        system/Ethernet.    -   Extensions within the field bus-/Ethernet and in particular        real-time-Ethernet specifications or implementations of        completely new field bus systems may be carried out per software        update and do not require a new circuit.    -   In particular regarding two or more communication interfaces        within a circuit the particular field bus-/Ethernet systems will        be defined by loading the software and therefore may be combined        with a high flexibility.

Furthermore the task according to the invention is solved according toclaim 9. For this purpose a device for data communication is provided,in particular for coupling communicating among each other bus users ofan open automation system with distributed control functions via aserial data bus, which comprises:

-   -   a communication-controller, which cooperates with a superior        control unit and which provides at least one freely-programmable        communication-ALU,    -   a command code, on which several commands are encoded and which        is communication function optimised, and    -   a parallel arrangement of at least two logic function blocks in        the communication ALU, which carry out special communication        functions.        said communication functions not being definitively defined but        rather are formed on the basis of the freely-programmable and        communication function optimized communication ALUs, wherein        several commands are carried out in a system cycle and        transitions between the various networks can be carried out.

Compared to the design of a dedicated communication-controller throughprogramming of FPGAs (Field programmable Gate Array) or parts of itaccording to the state-of-the-art, which corresponds to a fixed wiredlogic, the device according to the invention provides theabove-described advantages. Furthermore unlike the conventional ALUscommands are carried out in one cycle in parallel. According to theinvention the logic function blocks are accordingly arranged in parallelin the communication ALUs and at the same time may process the commandcode, wherein even in case of high baud rates, i.e. I OOMHz Ethernet,the necessary functions may be executed.

As disclosed in DE 42 20 258 C2 a device for processing data ofbit-serially transferable data on a transmission line is known per se,said data, corresponding to a predetermined protocol for data transfer,may be transmitted in series, and within an interface before beingtransmitted are available as a data word or after having beentransmitted are reconstructable as a parallel data word, and whereinseveral commands may be carried out in a bit-clock of a system cycle. Indetail a bit processing unit is provided for an adaptation to aparticular predeterminable transfer protocol, which comprises optionallyselectable conversion elements, said conversion elements processingindividual data bits according to a particular protocol convention andbeing coordinated by a control unit. Said bit-processing unit at leastprovides one comparator for data bits following each other in sequence,the output signal of which is sent to the control unit. Further acoupling element is arranged between the transmission line and thebit-processing unit, said coupling element being designed as decoderunit or as encoder unit for the data output. For increasing theoperating speed in case of timely nested communication and processingprocedures to be processed the bit processing unit, the coupling elementand two switchable and via the control unit optionally activatable RAMsare connected to an internal bus. Further for changing the sequence ofbits dependent of an individually predetermined protocol structure oneof the conversion elements of the bit processing unit may be designed asa bit changer. In particular regarding protocols with differentsequences of bit priority said bit changer is designed such that it mayreflect a bit being arranged within a data word at the middle of saiddata word. One of said conversion elements of the bit-processing unit isdesigned as a sorting unit, thus allowing inserting a serial bit at anyplace of a data word. In order to ensure a sufficiently high processingspeed, for example within the range of 1 Mbit/s, said conversionelements are implemented mainly by means of circuit design. In contrastthereto the device according to the invention—as a result of theflexible command set and the belonging to it logic function blocks—maysolve several tasks in parallel in a much higher system cycle, that is100 MHz, and event-controlled, wherein a high processing speed may beobtained independent of protocols. Regarding the device disclosed in DE42 20 258 C2 a special communication solution has been developed,according to the state-of-the-art, for the transfer of data on the DataLink Layer (layer 2), without taking into account higher network layersand user-close services, like the configuration of parameters ornetwork-management. Regarding office—and home applications according toIEEE 802.11 as a rule it is not important, whether the data transferstagnates in cases of a higher network load and a telegram has to berepeated. In the automation technology the cyclic data exchange with theindividual users (devices) has to be ensured, that is within a definedperiod of time a fixed data volume has to be transferred. The solutionaccording to the invention also ensures the transfer of time-sensitivedata, so that a high Quality of Service (QoS) and a network migrationmay be obtained, for example to migrate a CAN-bus to a Ethernet-spherebeing up to one hundred times quicker. Further in a preferable way theinitializing of new and the exchange of faulty devices may be carriedout by plug & play and the flexible communication mechanisms simplifythe use in many applications and system architectures. According to theinvention the use of a gateway, which has to reformat application data,that is a device, which translates the services of one application layerinto the other application layer, causing much effort, in particularregarding bit-oriented data, is not required. According to the inventionthe connection between a bus system and a network is provided throughimplementation on the data link layer, whereby for example CAN-messagescan be translated into Ethernet-messages, as the higher protocols(application layer) are identical. In particular not onlyMaster/Slave-systems, but also distributed control units, which requireat least partially non-hierarchical network architecture with apermeability into both directions, may be established.

The task according to the invention is further solved according to claim14. An apparatus with flexible communication structure, in particularprogrammable controller, providing:

-   -   at least one freely-programmable communication controller        cooperating with a superior control unit,    -   at least one freely-programmable communication-ALU integrated in        the communication-controller and    -   an exchangeable, physical interface being connected to the        communication controller via signal lines for the transfer of an        identification code, control data, input and output data,        said physical interface thus being exchangeable.

The programmable controller, according to the invention, permits in avery simple way to make up a “quasi firm” communication controller, saidcommunication controller being made up of one or severalfreely-programmable communication ALUs (Arithmetic and Logic Unit), saidALUs providing a communication function optimized command set andhardware architecture. According to the invention the followingadvantages are accordingly provided:

-   -   The physical interface, formed as an exchangeable module, is        essentially smaller, cost-efficient and connected to the freely        programmable communication controller in the programmable        controller by one out- and input-line and a few control lines.        In contrast thereto about 40 signal lines are otherwise required        for data-, address- and control-line-bus of the usual Dual-port        Memory coupling, said coupling comprising much higher frequent        signals and limiting the connection to a length of a few        centimeters.    -   Based on the few signal lines the exchangeable physical        interface may be placed at any other place in the programmable        controller by means of a flexible connection.

The task according to the invention is further solved according to claim19. A method for data communication is provided, in particular for theconfiguration of an apparatus with flexible communication structure, inparticular a programmable controller, with at least onecommunication-controller, with at least one communication ALU integratedtherein and at least one physical interface, wherein

-   -   the communication functions are not definitively defined but        rather are formed on the basis of the freely-programmable and        communication function optimized ALUs,    -   the physical interface sends an identification code on a signal        line to the communication controller during the start phase and        said communication controller automatically carries out the        right configuration and loads the assigned to it software into        the communication ALUs.

According to the invention the following advantages are provided:

-   -   The development, production and sale of such a programmable        controller with exchangeable, physical interface circuit may be        carried out independent of a specific field bus system.    -   Extensions within the field bus specification or implementations        of completely new field bus systems may be carried out per        software update and do not require a new interface circuit.    -   In particular in case of two or several communication interfaces        the particular field bus systems are defined by loading the        software and therefore may be selected with a high flexibility.

The task according to the invention is further solved according to claim20. For this a method for data communication is provided, in particularfor synchronizing bus users of an open automation system withdistributed control functions, said bus users communicating among eachother on a serial data bus and comprising a “quasi firm”communication-controller, said communication-controller cooperating viaat least one freely-programmable communication ALU with a downstreamcontrol unit, wherein

-   -   said communication-controller detects the occurrence of a        specific data or event,    -   said communication ALUs carry out the synchronous control        functions and    -   between the synchronization times measurements and correcting        variables are exchanged with the downstream control unit,        said interrupt-latencies of the downstream control unit not        affecting the direct synchronization of the control functions.

According to the invention the method provides in a very simple way,while maintaining the modular structure, the communication via acycle-synchronous and equidistant bus for the control of highly preciseprocesses in shortest cycle times. According to the invention thecontrol and communication solution is based on a “quasi firm”communication-controller, said communication controller being made up ofone or several freely-programmable communication ALUs, said ALUsproviding a communication task optimized command set and hardwarearchitecture. According to the invention the following advantages areprovided:

-   -   The development, production and sale of such a circuit may be        carried out independently of a specific field bus system.    -   Extensions within the field bus specification or implementations        of completely new field bus systems may be carried out per        software update and do not require a new interface circuit.    -   In particular in case of two or several communication interfaces        the particular field bus systems are defined by loading the        software and therefore may be selected with a high flexibility.    -   According to the invention the combined control and        communication solution may be implemented despite complying with        real-time critical demands with reasonable expenditures and        provides—as a result of a continuous programming and shared data        keeping (all identifiers are automatically known system-wide and        unambiguous)—still enough space for future expansions, for        example to parallel processes, insert sub-routines, operate        analog and digital in and outputs on demand and optionally        operate axles individually or with different dependencies        towards each other.

The task according to the invention is further solved according to claim21. For this a method for data communication is provided, in particularfor synchronizing bus users of an open automation system withdistributed control functions, said bus users communicating among eachother on a serial data bus and providing a “quasi firm”communication-controller, said communication-controller cooperating atleast via one freely-programmable communication ALU with a downstreamcontrol unit, wherein

-   -   at start point of cyclically running control functions the        synchronized local time is stored,    -   by computing the difference with the stored time at the last        start point the cycle time is measured based on the local time        and    -   by enlarging or reducing the current cycle time, said cycle time        in relation to the local time can be kept constantly and in a        firm phase relation,        said entire cycle thus being synchronized to the local time in        its cycle time as well as in its phase position.

Compared to the method according to claim 20, wherein said “quasi firm”communication controller carries out a direct synchronization of thecontrol functions without the downstream control unit, thesynchronization according to claim 21 is carried out in accordance witha stored local time at every start point of a control function.Regarding both methods the interrupt latencies of the downstream controlunits do not affect the synchronization of the control functions,wherein described second method requires some more hardware expendituresfor maintaining a local time.

The task according to the invention is finally solved according to claim24. For this a device for data communication is provided, in particularfor the synchronization of communicating among each other bus users ofan open automation system with distributed control functions on a serialdata bus with:

-   -   a “quasi firm” communication-controller, which at least provides        one freely-programmable communication ALU,    -   a control unit downstream to the communication controller and    -   at least one logic function block with means for measurement and        storage of times in the communication ALU,        said communication controller carrying out a direct        synchronization of the control function without the downstream        control unit or the synchronization is carried out at every        start point of a control function in accordance with a stored        local time.

This design of the invention has the advantage that two powerful methodsmay be used without requiring a basic hardware adaptation. This may beattributed to the integrated, simply parameterizable drive parameters bythe interface programming in the “quasi firm” communication controller.

As a further design of the invention according to claim 15, thecommunication processor comprises several freely programmablecommunication-controllers.

This further design of the invention has the advantage, that themicroprocessor necessary in the exchange module and the assigned to itinfrastructure like memory and Dual-port-Memory for each channel may besaved compared to the state-of-the-art.

According to claim 16 the physical interface may be preferably designedas a printed circuit in the line connection.

This design of the invention has the advantage that as a result of thesmall sizes of the physical interface, said interface may be designeddirectly as a printed circuit forming the plug connector of the lineconnection.

According to claim 18, the communication processor preferably processesthe application and the transfer protocol.

Due to their high efficiency microprocessors of today may process theapplication as well as the transmission protocol. Thereforeadvantageously a second microprocessor and the assigned to itinfrastructure like memory and Dual-port-Memory in the exchange modulemay be saved.

Further advantages and details may be learned from the followingdescription of preferred designs of the invention taking into accountthe drawings, which show:

FIG. 1 the functional block diagram of a communication-processor with afreely-programmable communication-controller,

FIG. 2 the functional block diagram of a freely-programmablecommunication-controller for a communication processor according to FIG.1 and

FIG. 3 an example for a command code according to the invention,

FIG. 4 the functional block diagram of a programmable controller withflexible communication structure according to the invention,

FIG. 5 the functional block diagram of one design with directsynchronization of drive functions,

FIG. 6 the functional block diagram of a second design with storage ofsystem time with every start of a drive function and

FIG. 7 a time diagram with synchronization of the PWM-cycle to the localsystem time for the design of FIG. 6 according to the invention.

Already for years different communication systems with standardizedcommunication services and protocols, being able to communicate betweenheterogeneous and homogenous networks, are used in the automationtechnology. On the lower level there are arranged for example simplesensor-actuator-bus systems or back plate bus systems (for examplemodular input- and output devices to be placed on commercially availablestandardized mounting rails), on the middle level “embedded” networksfor the controlling of machines (which connect programmable controllers,complex electrical and hydraulic driving devices, input-/output-devices,data acquisition devices or man-machine interfaces) and on the upperlevel networks for fabrication automation. According to the inventionand with respect to communication relations a coherent logic network isdesigned such that a sharp dividing line between the technique in usualtelecommunication networks, described as follows, and computer datanetworks may not be clearly drawn any more.

In the telecommunication technology as a rule the data transfer ofcontinuous data streams, for example speech or video communication, iscarried out via packet switched communication networks, like for exampleLANs (Local Area Networks), MANs (Metropolitan Area Networks) or WANs(Wide Area Networks). Increasingly also the ADSL-technique (AsymmetricDigital Subscriber Line, asymmetrical DSL-data transmission technology)is used. Beside the ADSL-technique also other DSL-techniques are used,for example HDSL=High Data Rate Digital Subscriber Line; SDSL=SingleLine Digital Subscriber Line; MDSL=Multirate Digital Subscriber Line;RADSL=Low Rate Adaptive Digital Subscriber Line and VDSL=Very High RateDigital Subscriber Line, which may be optimized for each application andare summarized under the generic term xDSL-transmission technique. Thecommunication is provided via connections having various bandwidths,i.e. for example 56 KBit analog connection or 64 KBit-ISDN or DSL or—asfar as integrated in a LAN—via 100 MBit twisted-pair-line, or viaswitched connections 2 MBit and better, or via dedicated lines X 25.Accordingly a plurality of interface devices is known, for example:

-   -   ISDN S₀—interfaces,    -   LAN-Interface FE (with program storage) to PCI-Bus,    -   external LAN-Interface LAN (with program storage) as 10/100        Mbit/s Ethernet or Token-Ring,    -   WAN-interfaces WAN: X.21, V.35, G.703/704 up to 2 Mbit/s.

All interactions of the user are then fed into the dialog between userand an interactive server through events and in a dialog control DE thesession-ID is stored as an account. The hardware concept of theinteractive server has to be adapted to the various, grown connectionstandards in the worldwide network operation. Specially adaptedLAN-modules with optional BNC-, AUI-, LWL- or Twisted Pair-Connectionsconnect the interactive server with local Token-Ring- andEthernet-networks. Access to wide area networks (i.e. ISDN, X 25) anddedicated lines is provided by partly multichannel WAN-adapters (S_(O),U_(PO), U_(KO), X.21, V.24, V.35). Active WAN-adapters may be used inorder to obtain optimal performance. In the ISDN-range the protocolsDSS1, ITR6, NI-1, as well as Fetex 150 are available.

According to the invention FIG. 1 shows interfaces formed as a freelyprogrammable communication controller KC. According to the inventionsaid communication controller comprises three communication-ALUs, shownin detail in FIG. 2, that is:

-   -   the Receive Processing ALU (RPA) being responsible for decoding        received bit- or nibble (half a byte) serial data stream in        accordance with the transfer rate and converting said data        stream into a parallel form (i.e. byte, word or double word),    -   the Transmit Processing ALU (TPA) being responsible for encoding        data out of a parallel form into bit- or nibble serial data        stream and feeding said data into the line with the correct        transfer rate and    -   the Protocol Execution ALU (PEA) being responsible for        controlling the input- and output sequence of a related data        packet.

In order to be able to implement the necessary functions also with highbaud rates, for example 100 MHz Ethernet, the following requirements aremet according to the invention:

-   -   The communication ALUs RPA and TPA may carry out several        commands in parallel. According to the invention for this a wide        command code BC (see FIG. 3) is used, for example 64 Bit, on        which several commands (see FIG. 3: the seven most significant        bits, operation, condition, jump) are encoded. These may be, for        example, logical operations, program jumps, setting and deleting        of bits in the flags F, incrementing and decrementing of        counters, transfer of data and operating of specific function        registers. Unlike conventional ALUs said commands may be carried        out in parallel in one cycle. According to the invention        therefore the logic function blocks are arranged in parallel in        said communication ALUs and may process said command code BC at        the same time.    -   The communication ALUs RPA and TPA provide special function        registers, which also have an impact in parallel on the data to        be processed. In detail these are:        -   shifting registers Fl, to/from which serial data may be            shifted automatically in and out and make the insertion and            deletion of bits possible at any position,        -   counters Z, which automatically count serial data and            compare registers, which set a bit in case of equality,        -   comparing registers V, which compare serial data according            to particular bit patterns and in case of equality set a bit            in the flags F,        -   CRC-generators CRC, which automatically compute CRC-polynoms            from the bit-serial data,    -   Unlike conventional ALUs the communication ALU PEA monitors a        plurality of specific events per hardware in parallel. For        example this may be:        -   the transfer of specific data from the RPA or to the TPA or            to the superior CPU,        -   the lapse of time,        -   the monitoring of certain counter readings or        -   the setting of particular status bits.            If one or a particular combination of events takes place,            the communication-ALU PEA reacts within a system cycle            through processing a piece of program code assigned to the            event.    -   Further within one system cycle the communication ALU PEA is        able to:        -   read a data out of a local Dual Port Memory DPM,        -   process and        -   transfer to the communication-ALU TPA or rather from the            communication-ALU RPA        -   take over,        -   process and        -   store in the local Dual Port Memory DPM.    -   The access to the local Dual Port Memory DPM is carried out via        two registers twice indexed, in order to be able to access the        data structures being usually used in communication technology        within one system cycle.    -   According to the invention the interface between the        communication ALUs PEA and RPA or TPA is formed as FIFO, in        order to intermediately store incoming and outgoing data.    -   According to the invention the interface between the        communication controller KC and a superior control unit CPU is        formed as a DMA-controller DMA for the quick transfer of high        data volumes and also as a Dual-Port-Memory DPM for maintaining        status variables and as a shared register set SR for the        synchronization.    -   According to the invention for synchronizing the communication        ALUSs PEA, RPA or TPA among each other a set of shared registers        SR is provided on which each communication-ALU PEA, RPA or        rather TPA may write and read out.    -   The superior CPU may also access the shared registers SR in        order to monitor or control the communication status.

Further functions of the communication-ALU TPA, which are implementedper software regarding Ethernet-protocols, are: mapping the to be sentbytes, identifying collisions in half-duplex operation and executing aback-office-algorithm, providing the communication ALU PEA withtransmit-status-information after end of a transmission process,observing the rest time Inter-Packet Gap (IPG) between two telegrams,complementing outgoing data by a preamble, a Start-Off-Frame-Delimiter(SFD) and a parameterizable Cyclic-Redundancy-Check-Word (CRC), paddingof a telegram with pad-bytes in case the telegram length would be <60byte and aborting a transmission process on request. Further functionsof the communication ALU RPA are: placing received bytes at the disposalof the communication ALU PEA, identifying the Start-Of-Frame-Delimiterand a VLAN-Frame (Virtual-LAN), checking of the field length and theCRC-word in telegrams, placing Receive-Status-Information at thedisposal of the communication ALU PEA after end of a reception processand deleting the preamble and Start-Of-Frame-Delimiter in telegrams.

These communication ALUs PEA, RPA or TPA cooperate with the superiorcontrol unit CPU, which may be either integrated in the circuit or mayalso be arranged externally. If the superior control unit CPU isintegrated, the circuit may carry out the communication functions andaccordingly provides the Dual-port Memory DPMH for the connection withanother control unit (host system) or said circuit—apart from thecommunication—carries out the entire application and accordinglyprovides the internal system bus as an extension bus EB for theconnection with an external memory and periphery block. As a preferreddesign the host computer interface device provides a host control deviceHC connected to address-, data-, control bus lines, which may beswitched over between an extension bus EB for connection with a memoryand periphery blocks and the Dual-port Memory DPMH for connection with afurther superior control unit. For both operation modes it would makesense to use the same signals and to switch those over per software. Atthe same time the register set SR and the Dual-port Memory DPM of thecommunication-ALUs RPA, TPA, PEA may be read out and written on inparallel to the running operation of the superior control unit (CPU), sothat an industrial real-time Ethernet solution with network cycles and aprecision within a range of micro seconds may be obtained, which doesnot need any support of proprietary hardware components or ASICs. Thisalso applies for the optimization and adjustment of the real-timetransfer, like adaptation to the demands of the application, to thesystem and to the communication architecture, so that a constant dataaccess may be permitted from the management-level down to thefield-level.

As shown in FIG. 1 the device according to the invention also provides aData Switch DS, said data switch connecting for example a32-Bit-Control-Unit CPU and the other communication-ALUs PEA (wherein inFIG. 1 four separated communication controllers KC are shown) with amemory SP, the internal periphery PE and a dual-port memory DPMHassigned to the host control device HC. Said data switch DS avoids the“bottle-neck” of a shared bus known from other communication-processorsby enabling the master ports accessing at the same time data via thedifferent slave ports (two in the exemplary design).

As shown in FIG. 4 the programmable controller with flexiblecommunication structure according to the invention comprises a baseboard of said programmable controller AG providing acommunication-processor KP with at least one, four in the exemplarydesign, freely-programmable communication-controller KC. According tothe invention at least one of said freely programmablecommunication-ALUs KA is integrated in the communication-controller KC.As described above, said communications-ALUs KA are responsible todecode the incoming bit- or nibble- (half byte) serial data streamaccording to the transfer rate and to convert said data stream into aparallel form (i.e. byte, word, double word) and/or to encode data outof a parallel form into a bit- or nibble serial data stream and to feedsaid data into the line with the correct transfer rate and/or to controlthe input- and output sequence of a related data packet

Further said base board of the programmable controller AG provides atleast one, in the exemplary design four, physical interface beingconnected to the communication-controller KC via signal lines IC, ST,ED, SD, said interface transmitting a particular identification code,control data, input and output data. As shown in FIG. 4, saidcommunication-processor KP also provides a data switch DS, said switchfor example connecting a 32-Bit-Control-Unit CPU and thecommunication-controllers KC (wherein in FIG. 4 four separatedcommunication controllers KC are shown) with a memory SP, the internalperiphery PE and a host control unit HC. The host control unit HC may beswitched between an extension bus EB for connection with a memory andperiphery blocks and the dual-port memory DPMH for connection with afurther superior control unit. Said data switch DS avoids the“bottle-neck” of a shared bus known from other communication-processorsby enabling the master ports (in the exemplary design two) accessing atthe same time data via the different slave ports (in the exemplarydesign three). Then the memories and the dual-port memory DPM may beread out and written on in parallel to the running operation, so that anindustrial real-time Ethernet solution with network cycles and precisionwithin a ms-range may be obtained, which does not need any support ofproprietary hardware components or ASICs. This also applies for theoptimization and adjustment of the real-time transfer as well as for thecompliance with the demands of the application, of the system and thecommunication architecture, so that a constant data access may bepermitted from the management-level down to the field-level.

According to the invention said communication functions are notdefinitely defined, but rather are formed on the basis of freelyprogrammable and communication function optimized communication ALUs. Inthe start phase said communication-controller KC reads in theidentification code of a physical interface PS, afterwards configuresthe communication-ALU KA matching and automatically loads the belongingto it firmware. Further said communication-processor KP provides severalfreely programmable communication-channels and accordingly may implementany combination of communication-standards. In a preferred design of theinvention based on several freely-programmable communication-controllersKC said communication-processor KP may also—apart from thecommunication-protocols—process the application.

According to the invention said physical interface PS may be designed asan independent, exchangeable module without own intelligence or controlfunctions, said physical interface logging in by help of anidentification code on said freely-programmable communication-controllerKC during start phase and thus authorizes said communication-controllerKS to load the matching configuration and assigned to it firmware.According to the invention in particular not only master/slave-systems,which require at least partly non-hierarchical network architecture withpermeability in both directions, may be established, but alsodistributed control functions.

According to the invention in FIG. 5 a “quasi firm”communication-processor KP is shown, which provides at least one, in theexemplary design three, freely-programmable communication-controller KCwith three communication-ALUs RPA, TPA, PEA each. Said firstcommunication-ALU RPS is responsible, as described above, in accordancewith the transfer rate to decode the received bit- or nibble (half Byte)serial data stream and to convert said data stream into a parallel form(i.e. byte, word, or double word), said second communication-ALU TPA isresponsible, as described above, to encode data out of a parallel forminto a bit- or nibble-serial data stream and to feed the line with theright transfer rate and the third communication-ALU PEA is responsible,as described above, to control the input- and output sequence of arelated data packet

In FIG. 5 a preferred design of the invention is shown, wherein saidcommunication-controller KC provides the Pulse-Width-Modulation-stagePWM for driving the output stage of the motor, the encoder logic EL forreading in the actual-position and the sample-and-hold-stage SH and theanalog-digital-converter AD for measuring phase voltage and motorcurrent. In particular the position motor voltage and motor current orphase voltage is transmitted between communication-controller KC anddrive.

As shown in FIG. 5, said communication-controller KC also provides saiddata switch DS, said switch for example connecting said downstream32-Bit-Control-Unit CPU and said communication-ALUs KC with said memorySP and said internal periphery PE. Said communication-ALUs RPA and TPAmay process several commands in parallel. For this purpose a widecommand code BC may be used, as described above, for example 64 Bit, onwhich several commands are encoded. These may be for example logicaloperations, program jumps, setting and deleting of bits, incrementingand decrementing of counters, transferring data and operating specialfunction registers. Unlike conventional ALUs these commands may becarried out in one cycle. Accordingly said communication-ALU PEAmonitors a plurality of special events per hardware in parallel unlikeconventional ALUs. This may be for example:

-   -   the transfer of specific data from the communication-ALU RPA or        to the communication-ALU TPA or to the downstream CPU    -   the lapse of time,    -   the monitoring of particular counter readings or    -   the setting of certain status bits.

If one or a particular combination of events occurs, thecommunication-ALU PEA reacts within a system cycle by processing a pieceof a program code assigned to the event.

Furthermore within a system cycle said communication-ALU PEA may:

-   -   read out a data of a local memory SR,    -   process said data and transfer it to said communication-ALU TPA

or from the communication-ALU RPA may

-   -   receive,    -   process and store in the local memory SR.

The access to the local memory SR is carried out via two registers twiceindexed, in order to be able to access the usual data structures used inthe communication technology within one system cycle. Thus said dataswitch DS avoids, as described above, the “bottle-neck” of a shared busknown from other communication-processors KP by letting the master ports(in the exemplary design two) access data at the same time via thedifferent slave ports (in the exemplary design three). Therefore at thesame time the memories may be read and written in parallel to therunning operation, so that an industrial real-time Ethernet solutionwith network cycles and precision within a range of micro seconds may beobtained, which does not need any support of proprietary hardwarecomponents or ASICs. This also applies for the optimization andadjustment of the real-time transfer as well as for the complying withthe demands of the application, of the system and the communicationarchitecture, so that a constant data access may be provided from themanagement-level down to the field-level.

According to the invention said communication functions are notdefinitively defined, but rather are formed on the basis of freelyprogrammable and communication function optimized communication ALUs KA.In the start phase said communication-processor KP configures saidcommunication-controller KC matching and automatically loads theassigned to it firmware. Further said communication-processor KPcomprises several freely programmable communication-controllers KC andwith those may implement any combination of communication-standards.

As a preferred design of the invention beside the communicationprotocols said communication-processor KP may also carry out theapplication based on several freely programmablecommunication-controllers KC. According to the invention, as shown in apreferred design in FIG. 5, said freely-programmable communication-ALUsRPA, TPA, PEA work absolutely deterministically and automaticallyexecute the synchronous drive functions without the downstream controlunit CPU. Between synchronization times the measured values (position ormotor current or phase voltage) transmitted via both encoder logics ELor a Sample-Hold-switch SH and an AD-converter AD or the correctingvariables transmitted via a PWM modulator PWM are exchanged with thedownstream CPU. Thus the interrupt latencies of the CPU will be ignoredregarding the synchronization of the drive functions. According to theinvention, a direct synchronization of drive functions, in particularthe measuring of the position or the output of correcting variables, isprovided on quick, deterministic and jitter-free communicationconnections, in particular real-time-Ethernet connections like forexample PROFINET, POWERLINK, SERCOS-3, EtherCAT.

Alternatively the drive may maintain a local time, which may besynchronized via communication connections to local times of otherdrives on a shared system time within a programmable controller. Atfirmly defined points in time synchronous functions like measurement ofposition or output of motor current may then be carried out on eachdrive. Particularly difficult may be deemed that functions needed forthis process run cyclically and that the entire cycle has to besynchronized in its cycle time and in its phase stage to the local time.A further design of the invention is shown in FIG. 6 and compared to thedesign shown in FIG. 5 this design provides additionally a local clock Uand in the connection path of each of the communication-ALUs RPA, TPA,PEA a latch L is arranged. At the start point of cyclically runningcontrol functions the synchronized local time will be stored in saidlatch L, by computing the difference with the stored time in said latchL at the last start point the cycle time is measured based on the localtime U and finally by enlarging or reducing the current cycle time, saidcycle time is kept constantly and in a firm phase position. The entirecycle is then synchronized in its cycle time as well as in its phaseposition to the local time, as this can be learned directly from thetime diagram shown in FIG. 7. According to the invention a directsynchronization of cyclic drive functions, in particular the measuringof the position or the output of correcting variables, to a local systemtime is permitted, said system time being able to be readjusted byappropriate protocols, in particular IEEE 1588, to obtain a synchronismwithin the automation system.

Even if the design of the invention is primarily described for theapplication in the automation technology, in particular for drivefunctions, (including an universal communication-platform for barcode-and identification systems, intelligent EAs, Low-Cost-drives, SPSs ormachine terminals), the application of the method and apparatus may alsobe conceivable in other communication networks with correspondingnetwork transitions. Standard and safety functions may be combinedwithin a system without retroactive effects through an intelligentinterlocking of both said functions. The modularity of said systemsprovides a high user-flexibility for customized, always easilyexpandable solutions and also permits a migration. This may be explainedby the fact that according to the invention the concept is based onalready given prerequisites of communication networks orsystems/facilities (also for switched connections) thus permitting theeasy adaptation to particular circumstances and the migration of theunchanged invention or of the basic concept. For example, according tothe invention the method permits a cost-efficient design of bus userswith individual interactive communication, said bus users being suitablefor optional networking via optional wireless or wire networks ortelecommunication networks (for example UTRAN UMTS Terrestrial RadioAccess Network). The iteratively running process of the networkmanagement service, in particular regarding the dialog, comprises allusefully occurring dialog elements (for example initialization,configuration, start and stop of bus users (devices) or programs,communication protocols), which are backed up correspondingly, and mayalso be applied in particular regarding inhomogeneous structures andpermits a dialog monitoring with inclusion of the bus users and thedialog server in the telecommunication network. Thus for example anaccess to data, parameters, functions is permitted on each bus user,said access being carried out of any location via internet as well as astandard, device-independent fault clearance. Furthermore in apreferable way the initializing of new and the exchange of faultydevices may be carried out through plug & play and the flexiblecommunication mechanisms permit the simple use in many applicationrequirements and system architectures. According to the invention forexample not only master/slave-systems, but also distributed controlfunctions requiring at least partly non-hierarchical networkarchitecture with a permeability into both directions, may beimplemented. As a further design of the invention for examplerouting-functionalities (also as LCR Least Cost Router) may be installedin the dialog server for TCP/IP and SPX/IPX.

1-24. (canceled)
 25. A method for data communication and for couplingmutual communication among bus users of an open automation system withdistributed control functions via a serial data bus, the bus userscooperating with a superior control unit via a communication controller,the method comprising the steps of: a) providing thecommunication-controller with at least one freely-programmablecommunication-ALU; b)encoding several commands on a command code for thecommunication-ALU, the command code being optimized for particularcommunication functions; and c) arranging logic function blocks inparallel in said communication ALU, the function blocks carrying outparticular communication functions, wherein the communication functionsare not definitively defined, rather formed on a basis offreely-programmable and communication function optimized communicationALUs, several commands being carried out in system cycle with executionof transitions between various networks .
 26. The method of claim 25,wherein communication is carried out in two steps, the communicationfunction being assigned to two communication ALUs of a first step,wherein a first communication-ALU is optimized for receiving anddecoding a bit- or nibble-oriented, serial data stream, and for parallelconversion into byte-, word- or double-word-form, and a secondcommunication-ALU is optimized for the serial conversion of byte-, word-or double-word-form into bit- or nibble-oriented, serial data, and forencoding and transmitting the serial data stream, the communicatingfunction further assigned to a communication-ALU in a second step,wherein a third communication-ALU, provides a monitoring logic tomonitor a plurality of possible events or combinations of those at asame time and which, in case of an event occurrence, starts an assignedprogram code within one system cycle.
 27. The method of claim 26,wherein the superior control unit is integrated in a circuit togetherwith one or all of said communication-ALUs, said circuit providing adual-port memory for connection to an external control unit or whereinthe superior control unit of the circuit carries out an entireapplication and said circuit then provides an internal system bus formedas an extension bus to connect an external memory and periphery blocks,wherein, for both operation modes, same signals are used which areswitched per software.
 28. The method of claim 25, wherein a very wideor a 64 bit wide command code is used, on which several commands,logical operations, program jumps, setting and deleting of bits,incrementing and decrementing of counters, data transfer and operationof special function registers, are encoded, said commands beingprocessed in parallel within one system cycle.
 29. The method of claim26, wherein the third communication ALU monitors, in parallel, aplurality of particular events or a transfer of particular data from thefirst communication ALU to the second communication ALU, to the superiorcontrol unit, a lapse of time, particular counter readings, or settingof particular status-bits.
 30. The method of claim 27, whereincommunication ALUs are coupled to further communication-ALUs via ashared register set for serial/parallel- or parallel/serial-conversion,the communication ALUs permitting write and read access for all users ata same time, wherein, regarding writing, a last value is valid.
 31. Themethod of claim 30, wherein a register set and a dual-port memory of thecommunication-ALU is read and written by the superior control unit inparallel to a running operation mode.
 32. The method of claim 30,wherein the communication-controller comprising at least onecommunication-ALU is coupled to the superior control unit via aDMA-controller, a dual-port memory, and a shared register.
 33. A devicefor data communication and for coupling mutual communication among bususers of an open automation system having distributed control functionsvia a serial data bus, the device comprising: a communication controllercooperating with a superior control unit and having at least onefreely-programmable communication-ALU; a command code on which severalcommands are encoded and which is communication function optimized; anda parallel arrangement of at least two logic function blocks executingparticular communication functions in said communication ALU, whereinsaid communication functions are not definitively defined, rather formedon a basis of at least one freely-programmable and communicationfunction optimized communication-ALU, several commands being carried outin a system cycle with execution of transitions between variousnetworks.
 34. The device of claim 33, wherein said arranged in parallellogic function blocks comprise at least one shifting register, at leastone counter, and at least one comparator which evaluate serial data andset status-bits in flags depending on predetermined values, and with atleast one CRC-generator which, upon command of said communication-ALU,includes the serial data when computing a CRC-polynom forserial/parallel- or parallel/serial-conversion of one up to 32 bit widedata and encoding and decoding of that data.
 35. The device of claim 33,wherein, for serial/parallel- or parallel/serial-conversion, saidcommunication-ALU is coupled to further communication-ALUs via FIFOs andadditionally via command- and status registers or wherein said furthercommunication-ALUs are coupled via a shared register set, saidcommunication ALUs permitting write and read access for all users at asame time, wherein regarding writing, a last value is valid.
 36. Thedevice of claim 33, wherein at least one said communication ALU isconnected to said superior control unit via a DMA-controller and/or adual-port memory.
 37. The device of claim 36, wherein a host interfaceunit is provided with a host control unit connected to address-, data-,control bus lines, said host control unit switching over between anextension bus, for a connection of memory and periphery blocks, and saiddual-port memory for connection of a further superior control unit. 38.An apparatus with flexible communication structure or a programmablecontroller, the apparatus comprising: at least one freely-programmablecommunication-controller, cooperating with a superior control unit; atleast one freely-programmable communication-ALU integrated in saidcommunication-controller; and an exchangeable, physical interfaceconnected to said communication-controller via signal lines fortransmission of an identification code, control data, input data, andoutput data.
 39. The apparatus of claim 38, wherein a communicationprocessor comprises several freely programmablecommunication-controllers.
 40. The apparatus of claim 38, wherein saidphysical interface is a printed circuit forming a connecting plug of acommunication network.
 41. The apparatus of claim 38, wherein thephysical interface, with a connecting plug of a communication network,is designed as an integrated unit.
 42. The apparatus of claim 38,wherein said communication processor processes both application andtransmission protocol.
 43. A method for configuration of a programmablecontroller having at least one communication controller in which atleast one communication-ALU is integrated and with at least one physicalinterface, the method comprising the steps of: a) forming communicationfunctions in a manner which is not definitively defined, rather on abasis of freely-programmable and communication function optimizedcommunication ALUs; b) transmitting, during a start phase and using thephysical interface, an identification code to said communicationcontroller via a signal line; and c) automatically executing a properconfiguration using the communication controller to load assignedsoftware into the communication-ALU .
 44. A method for synchronizationof mutual communication among bus users of an open automation systemwith distributed control functions via a serial data bus and having aquasi-firm communication controller cooperating with a downstreamcontrol unit via at least one freely-programmable communication-ALU, themethod comprising the steps of: a) detecting, with the communicationcontroller, an occurrence of particular data or an event; b) executing,with the communication ALU, synchronous control functions; and c)exchanging, between synchronization points of time measurements,correcting variables with the downstream control unit such thatinterrupt latencies of said downstream control unit do not affect directsynchronization of the control functions.
 45. A method forsynchronizating mutual communication among bus users of an openautomation system with distributed control functions via a serial databus having a quasi-firm communication controller cooperating with adownstream control unit via at least one freely-programmablecommunication-ALU, the method comprising the steps of: a) storing asynchronized local time at a start point of cyclically running controlfunctions: b) computing a difference with a time stored at a last startpoint to measure a cycle time based on a local time; and c) enlarging orreducing a current cycle time, to keep the cycle time in constant andpermanent phase relationship, wherein an entire cycle is synchronized tothe local time with respect to cycle time as well as phase position. 46.The method of claim 44, wherein a direct synchronization of drivingfunctions, a position measurement, or output of correcting variables, isprovided on quick, deterministic, and jitter-free communicationconnections.
 47. The method of claim 45, wherein direct synchronizationof cyclic driving functions, position measurement, or output ofcorrecting variables, is effected to a local system time being able tobe readjusted by appropriate protocols or by IEEE 1588, thus achievingsynchronism within the automation system.
 48. A device forsynchronization of mutual communication among bus users of an openautomation system with distributed control functions via a serial databus, the device comprising: a quasi-firm communication controller,having at least one freely-programmable communication-ALU; a controlunit (CPU) disposed downstream of said communication controller; and atleast one logic function block having means for measuring and storingtimes in said communication ALU, wherein said communication controllereffects direct synchronization of the control functions without saiddownstream control unit or said synchronization is carried out accordingto a stored local time at every start point of a control function.